1. Field of the Invention
The invention relates to a system for internally inspecting a machine, such as an engine, by optical fibre endoscopy, and is applicable to machines having zones which are inaccessible for inspection and in particular to the turbomachines which form part of aircraft engines.
2. Summary of the Prior Art
In order to inspect internal critical zones of a machine, especially an aircraft engine, it is known to use an endoscope, and French Patent 2 443 697 discloses an example of this. The endoscope is introduced into localised entry apertures in walls and/or partitions of the machine for inspecting zones disposed in the locality of the entry apertures.
FIG. 1 shows a diagrammatic sectional view of an example of a turbomachine compressor provided, in accordance with the prior art, with three entry apertures extended by rigid walled passages for the endoscopy of three different critical zones. The three critical zones 1, 2, 3 to be inspected are stages of bladed discs disposed downstream of the compressor. The entry zones and the rigid walled passages 4, 5, 6 permit the introduction and positioning of an endoscope. Each walled passage enables a single compressor stage to be inspected by endoscopy. The zones which can be inspected are limited since endoscopic examination of a critical zone is possible only when an aperture can be provided near the zone. Also, the engine wall must be formed with a plurality of entry apertures and walled passages if it is to be possible to inspect different internal zones which are remote from one another.